The Ford Barn

39portlander · 02-25-2017, 06:02 PM

I pulled these out of the head on my 26 Fordor the first one (RH) has the longer porcelain and #25, the middle two are 407 and the last one 517.

I plan on just cleaning them up and reusing them but wondering if those different numbered plugs are different temps and I should get four that are all the same. Any input would be great.

Royce P · 02-25-2017, 06:50 PM

Sponsored Links (Register now to hide all advertisements)

They are different heat ranges. I think the A25 would be the hottest, the one on the right the coldest. I would put the A25 in #1 and then keep them in order with the coldest plug at the rear.

02-25-2017, 06:02 PM	#1
39portlander Senior Member Join Date: May 2010 Location: Suth'N Maine Posts: 1,996	Spark plug numbers... I pulled these out of the head on my 26 Fordor the first one (RH) has the longer porcelain and #25, the middle two are 407 and the last one 517. I plan on just cleaning them up and reusing them but wondering if those different numbered plugs are different temps and I should get four that are all the same. Any input would be great. Last edited by 39portlander; 04-15-2018 at 06:04 PM.

02-25-2017, 06:50 PM	#2
Royce P Senior Member Join Date: May 2010 Location: Tulsa OK Posts: 476	Re: Spark plug numbers... Sponsored Links (Register now to hide all advertisements) They are different heat ranges. I think the A25 would be the hottest, the one on the right the coldest. I would put the A25 in #1 and then keep them in order with the coldest plug at the rear. __________________ 1910 Touring 1914 Touring 1915 Touring 1917 Torpedo Runabout